On the Business Central Cloud, to save a report in PDF format and change its name while saving, you can use a STREAM BLOB through the “Temp blob” codeunit.
Once this is done, use the function then the BLOBExport function present in the “File Management” codeunit to export the report created with the “REPORT.SAVEAS” command, changing its name during saving.
Source : Roberto Stefanetti Blog – Microsoft Dynamics 365 Business Central
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